title: Genotyping and antimicrobial resistance patterns of Escherichia coli O157 originating from cattle farms.
abstract: During a Escherichia coli O157 prevalence study on cattle farms, 324 E. coli O157 isolates were collected from 68 out of 180 cattle farms. All isolates harbored the eaeA gene and the enterohemolysin (ehxA) gene. The majority of the strains only contained vtx2 (245 isolates), the combination of vtx1 and vtx2 was detected in 50 isolates, and in 29 isolates none of the vtx genes was present. Pulsed-field gel electrophoresis (PFGE) revealed that at a similarity level of 98% the isolates grouped into 83 different genotypes, 76 of which were only detected on one farm. Twenty-two out of the 68 positive farms harbored isolates belonging to more than one PFGE type, with a maximum of four different PFGE types. Minimal inhibitory concentrations of 10 antimicrobial agents were determined on a subset of 116 isolates, that is, one isolate per positive age category per farm. Acquired resistance to at least one antimicrobial agent was detected in 18 isolates and within a farm, only one resistance pattern was observed. All these 18 isolates were resistant toward streptomycin, and 16 of them also showed resistance toward sulfisoxazole. Six isolates were resistant to three or more antimicrobial agents.
authors.affiliation: Department of Veterinary Public Health and Food Safety, Ghent University, Merelbeke, Belgium.
authors.forename: Katrijn
authors.initials: K
authors.lastname: Cobbaut
authors.forename: Kurt
authors.initials: K
authors.lastname: Houf
authors.forename: Filip
authors.initials: F
authors.lastname: Boyen
authors.forename: Freddy
authors.initials: F
authors.lastname: Haesebrouck
authors.forename: Lieven
authors.initials: L
authors.lastname: De Zutter
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001530:Belgium; D002417:Cattle; D024881:Drug Resistance, Bacterial; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field / Q000662:veterinary; D004783:Environmental Microbiology; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D014644:Genetic Variation; D005838:Genotype; D006460:Hemolysin Proteins / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D022622:Shiga Toxin 1 / Q000235:genetics / Q000378:metabolism; D022641:Shiga Toxin 2; D022603:Shiga Toxins / Q000235:genetics / Q000378:metabolism; D013307:Streptomycin / Q000494:pharmacology; D013444:Sulfisoxazole / Q000494:pharmacology; D014774:Virulence / Q000235:genetics; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D018829:Adhesins, Bacterial; D000900:Anti-Bacterial Agents; D029968:Escherichia coli Proteins; D006460:Hemolysin Proteins; C036507:Hlya protein, E coli; D022622:Shiga Toxin 1; D022641:Shiga Toxin 2; D022603:Shiga Toxins; D037521:Virulence Factors; C430449:verocytotoxin 2; C073819:eaeA protein, E coli; D013444:Sulfisoxazole; D013307:Streptomycin